Systems and methods for post combustion mercury control using sorbent injection and wet scrubbing

Abstract

A sorbent composition for removing mercury from flue gas, including a powdered sorbent having a fifty percent distribution particle size of from about 20 micrometers to about 75 micrometers. The invention also include a method of cleaning flue gas, the method including injecting a powdered sorbent into the flue gas, wherein the powdered sorbent has a fifty percent distribution particle size of from about 20 micrometers to about 75 micrometers.

What is claimed is: 
     
       1. A sorbent composition for removing mercury from flue gas, comprising:
 a powdered sorbent having a fifty percent distribution particle size of from about 25 micrometers to about 75 micrometers, 
 wherein said sorbent composition does not contain halogen and said powdered sorbent improves mercury removal from flue gas without halogen. 
 
     
     
       2. The sorbent composition of  claim 1 , wherein the powdered sorbent has a fifty percent distribution particle size of from about 30 micrometers to about 75 micrometers. 
     
     
       3. The sorbent composition of  claim 1 , wherein the powdered sorbent is powdered activated carbon. 
     
     
       4. The sorbent composition of  claim 1 , wherein the powdered sorbents reduce mercury concentrations in the air phase. 
     
     
       5. The sorbent composition of  claim 1 , wherein the powdered sorbents reduce mercury concentrations in the water phase. 
     
     
       6. A method of cleaning flue gas, the method comprising:
 injecting a powdered sorbent into the flue gas, wherein the powdered sorbent has a fifty percent distribution particle size of from about 25 micrometers to about 75 micrometers, wherein said powdered sorbent does not contain halogen and said powdered sorbent improves mercury removal from flue gas without halogen; 
 collecting the powdered sorbent in a flue gas desulfurization system; and 
 removing the powdered sorbent from a dewatered slurry in a flue gas desulfurization system using a hydrocyclone in communication with the flue gas desulfurization system. 
 
     
     
       7. The method of  claim 6 , further comprising:
 removing the powdered sorbent from a dewatered slurry in a flue gas desulfurization system using a hydrocyclone in communication with the flue gas desulfurization system. 
 
     
     
       8. The method of  claim 7 , further comprising:
 removing particulates/solids with a vacuum filter after the hydrocyclone prior to liquor discharge. 
 
     
     
       9. The method of  claim 6 , wherein the powdered sorbent is powdered activated carbon. 
     
     
       10. A method of cleaning flue gas, the method comprising:
 injecting a powdered sorbent into the liquor/slurry of a flue gas desulfurization system, wherein the powdered sorbent has a fifty percent distribution particle size of from about 20 micrometers to about 75 micrometers. 
 
     
     
       11. The method of  claim 10 , further comprising:
 removing the powdered sorbent from dewatered slurry in a flue gas desulfurization system using a hydrocyclone in communication with the flue gas desulfurization system. 
 
     
     
       12. The method of  claim 11 , further comprising:
 removing particulates/solids with a vacuum filter after the hydrocyclone prior to liquor discharge. 
 
     
     
       13. The method of  claim 10 , wherein the powdered sorbent is powdered activated carbon. 
     
     
       14. The method of  claim 10 , wherein the powdered activated carbon improves mercury removal without halogens.